To provide a high-frequency power detector which prevents increase in a cost for receiving two or more of signal waves.

The detector is provided with a detected voltage output portion 806 which demodulates a high-frequency signal and outputs a detected voltage which follows the high-frequency signal, and a delay portion 810 which is connected in series to the downstream of the output portion 806, and delays the detected voltage. The delay portion 810 has a diode 812 for rectifying the detected voltage, and a resistor 814 for adjusting the quantity of delay of the detected voltage. The resistor 814 may be connected in parallel with the diode. Besides, the resistor 814 us a variable resistor, and it does not matter if a resistance control unit 90 which controls the value of the resistor 814 and controls the quantity of delay of the detected voltage, is provided.